Fixed bug CORE-3535 : Write target of dirty page could be undefined if error happens when nbackup state is changed.

Also prevent overwriting of first page of allocation table by data page contents.

Unregistered bug : Delete deferred work when savepoint is cleaned up after failure even if no records was modified. Else DFW task will be repeated at commit making system tables logically inconsistent.

Improvement CORE-3536 : Garbage collection in GTT is unnecessary delayed by active transactions in another attachments

Improvement CORE-3537 : There is no need to undo changes made in GTT created with ON COMMIT DELETE ROWS option when transaction is rolled back.

Backported fix for bug CORE-3502 : DROP VIEW ignores the existing non-column dependencies, andBackported fix for bug CORE-3503 : ALTER VIEW crashes the server if the new version has an artificial (aggregate or union) stream at the position of a regular context in the older version.

Unregistered bug : Delete deferred work when savepoint is cleaned up after failure even if no records was modified. Else DFW task will be repeated at commit making system tables logically inconsistent.

Backport improvement CORE-3536 : Garbage collection in GTT is unnecessary delayed by active transactions in another attachmentsBackport improvement CORE-3537 : There is no need to undo changes made in GTT created with ON COMMIT DELETE ROWS option when transaction is rolled back.

Fixed bug CORE-3509 : Alter procedure allows to add the parameter with the same name.